THE HABITATS OF IOWA SUCCINEAS

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The Nautilus.

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6 THE NAUTILUS [VoL 49 (1)

these light bands that pass over the top and the sides of this
terminal pouchy but there are none externally visible below^ as
that side is covered by the darker gland of the walls of the
deferent duct. Internally oviduct and deferent duct are already
separate. The deferent dnct lies below and is eovered above and
on the sides by the white walls of the oviduct enveloping the top
of the deferent duet with its thick glands. The diagonal bands
are due to folds of the walls of the oviduct which are more than
half a millimeter deep above and on the sides but much thinner
below. Evidently the deep narrow clefts between the diagonal
glandular folds account for the position of the ridges on the
outside of the eggshell. The oviduct walls also have muscle fibers
which doubtless play a part in forming the eggshell-

THE HABITATS OF IOWA SUCCINEAS

BY B. SHIMEK

The genus Succinea is often described as ^"amphibious/* Of
the species inhabiting Iowa this is strictly true only of S. retusa^
though S. concordialis inhabits the muddy borders of lakes and
streams (never^ however^ appearing in water) ^ where it may be
associated with retusa; while S. avara, though sometimes occur-
ring with S. retusa on low^ muddy flats^ also extends well up into
upland woods in contiguous territory, being our most adaptable
species.

The remaining species, ovalis and grosvenoriij display certain
peculiarities of habitat and distribution which are worthy of note,

Succinea ovalis Say is found in more or less scattered areas in
all wooded parts of the state. In the eastern part the writer
has almost invariably found it in low^ alluvial woods^ subject to
overflow. During flood times the animals creep up on the trunks
of trees and the stems of coarse plants which project above the
water; but at other times during the open season they may be
found creeping about on various plants, to which they may also
remain attached during drier parts of the day or season after
forming a thin, transparent epiphragm; or they may creep about
on the moist ground or hide under logs. During the late fall or
winter they hibernate under the fallen leaves of bottomland

July, 1935] the nautilus 7

trees, lying with the aperture uppermost^ the latter covered with
an opaque white epiphragm.

In 57 years of field experience in eajstern lowa^ the writer has
found but one exception to the rule that this species is found in
low alluvial bottomlands. In April, 1901, a scattered colony was
found at Iowa City on the rocky, wooded blufiE below what is now
the University President's house. They ranged from 25 to 75
feet above the river^ thus being entirely above the highest flood
level. After a prolonged search nearly 50 specimens were found,
all living. They were all under sticks and leaves, and none had
the winter epiphragm.

In the far western part of the state, however, this species is
distinctly more xerophilous, being found most frequently in
upland bur-oak groves, or in thickets bordering upon them,
where it occurs scattered ^ or in small colonies. The writer has
collected small sets in the border thickets on the high hills in-
cluded in and adjoining Fairmount Park at Council Bluffs, and
in upland, rather open, bur-oak groves in Mills, Harrison and
Monona Counties, in all cases on loess ridges, and in some cases
at heights fully 150 feet above the river-valley.

These western forms are usually somewhat smaller than the
more typical eastern forms, with a somewhat longer spire and
narrower aperture, but most of the bottomland specimens from
eastern Iowa are of much the same type, though occasionally
showing the larger form with broader aperture. The variation
of the entire series is much the same as that which occurs in the
loess fossils of this species in the same region, showing quite the
same range in both form and distribution.

Succmea grosvenorii Lea is the most unique of our species of
this genus, both in distribution and habitat. It has been found
as far north as Ft, Simpson on the upper Mackenzie River, and
it extends southward, east of the Rocky Mts., to Louisiana and
Texas, Eastward, however, it seems to be limited to close prox-
imity to the Missouri River, and to that of the Mississippi below
the mouth of the former.

In all this range, unlike most of the other species of the genus,
it is usually subject to xeric conditions, and this is true even of
the lower Mississippi region, as will be shown.

8 THE NAUTUiUS [Vol. 49 (1)

In most of the published reports of this species no habitat is
given^ — a very common fault of local reports on molluscs, — and
in several others the habitat, as given, is widely variant from
that which the writer has observed along its eastern limit. Thus,
Simpson (Conchologists' Exchange, voh I, 1887, p. 65) reports
it from the vicinity of Ogallala in western Nebraska, as abundant
*'in pools of alkali water near the South Platte River^ in early
spring/' Walker (Nautilus^ voL 20^ 1906, p, 81) states that it
occurs in the Salt Basin at Lincoln, Nebraska, and at Hackberry
Lake in Cherry County, of the same state. Hanna (Lc, vol, 23,
1909^ p, 96) says that in Douglas County, Nebraska, it was
**found in colonies in wet places,'^ while Over (Lc.^ p. 92) notes
it as common '^on plains and prairies.'' More recently, Cheatum
and Burt (Field and Laboratory, vol. II, no. 2^ 1934, p, 50)
report that in Dallas County, Texas, **it has been collected in
swampy regions, as well as under thin blankets of humus in
relatively dry areas/ ^ They refer it to localities (described in
Lc.f voL II, no. 1, 1933) which are mostly wooded and swampy.

With the exception of a small set collected in the Salt Basin
at Lincoln, Nebraska, in 1889, the writer has never found the
species living excepting on loess banks or bluffs along the Mis-
souri River in Iowa (as far north as Sioux City), Nebraska and
Missouri; on the west side of the Mississippi in Arkansas, and
on the east side of the same stream in Kentucky, Tennessee, Mis-
sissippi and Louisiana.

The specimens were usually few and scattered, and this was
true even in the two localities in which the species was obtained
in greatest numbers, namely, at Hamburg, Iowa, and Natchez,
Mississippi. In the former locality about 100 specimens were
collected, most of them dead, while in the latter about 500 living
specimens were secured after several days of incidental search.

Throughout this loess bluffs range the habits and habitat of
this species were quite uniform. In drier weather the scattered
individuals were found clinging to the bare faces of the loess
bluffs, or on the equally bare upper parts of the talus at their
base, and always on the more sheltered sides, either facing north,
or protected by turns and crevices in the bluffs.

When thus found, they almost invariably cling with the aper-

July, 1935] THE NAUTILUS 9

ture (covered by a thin, transparent epiphragm) pressed against
the face of the bluff. The epiphragm is quite readily dissolved
on the return of moisture, but equally readily formed when
necessary,

They creep about in moist er weather, or during the early
morning hours in drier periods, but close up promptly as soon
as dry conditions return.

In the north a few specimens have been found late in the
season^ evidently tucked away for the winter, with thick, opaque,
white epiphragms. These were found mostly in sheltered
crevices.

The habitat of this species on loess bluffs has probably been
overlooked by shell collectors because ordinarily no one would
look for land snails in such barren^ dry places. The writer's
innumerable contacts with loess exposures throughout the Mis-
sissippi and Missouri valleys, however, brought them to light
quite frequently.

It is evident that this species selects two quite different
major tabitats, namely, that noted above, and another on the
plains which may be quite moist or wet, but more or less alkaline
or saline. To the latter group belong those reported in the
references quoted above (with the exception of the last), and
also the sets which the writer has received from South Dakota,
Kansas and Texas.

Both types, however^ are distinctly xeric. The plains alkaline
ponds and moist spots are very drj^ during much of the average
summer, and even when wet, they are strongly xeric, as shown
by the character of their scant vegetation. The loess bluffs are
likewise subject to periodic xeric conditions^ and this is true even
in the southern mesie climate, for during drier seasons, and even
during different hours of the day, they may be quite dry. It
is evident, thereforej that this species is far removed in habit
from the co-generic "amphibious" and mesophilous forms, and
is a distinct xerophile.

As a loess fossil this species extends at least from Illinois to
Nebraska, and formerly thus evidently reached far beyond its
present eastern limits. It does not seem to be found in the far
southern loess, though the range of the modem form extends at

10 THE NAUTILUS [VoL 49 (1)

least to its southern limit. The food and resting habits of this
species are worthy of further study, and this should be under-
taken by those who live in the region of its occurrence.

It is certain that both S. grosvenorii and the upland form of
S. ovalis^ are quite xeropliilouSj the former somewhat more so,
and that both occur in closely contiguous places in the western
part of the state, sometimes so close together that they appear
to be mixed, just as they are in the loess. They, with other
species with which they are associated, again suggest that the
climate during the deposition of the loess of Iowa and vicinity
was not moist and cold, but may have been quite as warm and
dry as that of western Iowa is to-day.

The variation in habits and form of these species, quite as
strikingly duplicated in some others, should also lead to caution
in forming judgment concerning climatic conditions of past
periods of time. Hasty conclusions based on individual species
are always unwise; it is always safer to take entire faunas into
account. If this were done we might have fewer ** theories" and
wildly fantastic explanations, but some of our scientific work
would rest on a sounder foundation.

NEW SPECIES AND RACES OF LYMNAEIDAE FROM

NEWFOUNDLAND

BY FRANK C, EAKEB AND STAISTLEY T; BE00K8

In July, 1934 J the Junior author made a trip to the Island of
Newfoundland for the purpose of collecting its mollusean fauna.
This territory is, as far as the mollusks are concerned, almost a
ter^a incognita^ and it is not surprising that new forms should
be foundj since the region is completely isolated from the main-
land and from adjacent islands. A complete report or the
MoUusca collected will be published by the junior author,

Stagnicola palustris papyracea nov. var.

Shell differing from S. p. ungava F, C. Baker in being more
ovate with spire and aperture about equal in length, the whorls
of the spire not as high as in those of ungava^ the sutures less
deeply indented; inner lip narrow, the columellar plait quite
distinct and the umbilical <?hink small or absent; color light .

July, 1935 j THE NAUTILUS 11

honi^ interior of aperture light or dark chocolate color; sculpture
of finer lines than in ungmm. All apices are decollate and but
four whorls remain, but there are apparently six whorls in
mature examples.

Length 18. 6, diam, 10.5, apert. length 10,5, width 5,7 mm, Holotype
'' 181 '' 10.0 '' 10,5 '' 5Jmm, Paratype

" 17.1 '* 9,9 '' 9,5 '' 51mm. Paratype

Type locality: Rocky pond near Whitbourne, Newfoundland.
Types: Carnegie Museum, Section of Recent Invertebrates^ No,
62. 26761; Parafypes: Museum of Natural History^ Univ. 111.,
No. Z. 36336 J Academy of Natural Sciences^ Philadelphia^ No.
164120,

This race of palustris at once suggests S. p. itngava^ differing
in its shorter spire, narrower inner lip and distinct columellar
plait. It differs from S. p. elodes in its shorter less acute spire
and obese body whorL The shells are very thin which suggests
the varietal name. The thinness of shell is probably due to lack
of limestone rocks in the pond. The race is very constant in
form and does not appear to vary to any extent toward typical
palustris or its known varieties.

Stagnicola palustris perpalustris nov. var.

Shell obese, with large ovate aperture and short, dome-shaped
spire, the latter shorter than the aperture \ sutures well im-
pressed; outer lip thin with only a slight variceal thickening
within the edge j inner lip rather broad^ appressed tightly to the
columella leaving only a slight umbilical chink ; columellar plait
heavy, parietal wall with distinct callus; color dark horn, in-
terior of aperture dark chocolate colored; sculpture of hea\7^
growth lines and impressed spiral lines; surface often malleated;
only four whorls visible in mature shells^ all spires decollated.
Young shells indicate that there are probably six whorls in fully
mature shells.

Length 19 J, diam. 11, 3^ apert. length 12.0, width 6.6 mm, Holotype
'* 17.6 '' 10,4 '' 11.1 '' 6,0mm- Paratype

'' 111 '' 10.5 " 10.5 '' 5.8 mm, Paratype

Type locality: Pools along Exploits River, Grand Falls, New-
foundland, Types: Carnegie Museum, Section of Recent In-
vertebrates, No. 62, 26762; Parafypes: Museum of Natural His-
tory, Univ. 111., No. Z. 36337; Academy of Natural Sciences,
Phila., No, 164119.

12 THE NAUTILUS [VoL 49 (1)

This race of palustris is at once recognized by its broad form,
depressed spire and large aperture. It does not closely resemble
any of the described forms of this protean species, approaching
most closely to some short^spired forms of 8, p. nuttalliana from
the Rocky Mountain area.

Stagnicola newfoundlandensis nov. sp.

Shell elongated with acute somewhat turreted spire as long as
or longer than the aperture; spire whorls rounded with well im-
pressed sutures ; body whorl well rounded ; aperture ovate, outer
lip thin, inner lip flattened and reflected over the umbilical
region leaving a small chink; the callus on the parietal wall is
thin or absent; columellar plait absent or but slightly developed;
color dark horn, aperture coifee colored within; sculpture of
coarse growth lines and well developed spiral lines; there are
six whorls.

Length 20,0, diam. 9.9, apert, length 10.0, width 5.3 mm. Holotype
'' 22.0 '' 10.0 ** 10.0 '' 5.1 mm. Paratype

'' 18.8 '' 9.2 '* 9.0 '' 4Jmm. Paratype

'' 17.0 ** 9.0 ** 9.2 ** 5.1mm, Paratype

Type locality: Camp 31^ 8 miles from Lomond, Bonne Bay,
Newfoundland, Types: Carnegie Museum, Section of Eecent In-
vertebrates, No. 62, 26763; Paratypes: Museum of Natural His-
tory, Univ, Ill.j No. Z. 36338; Academy of Natural Sciences,
Philadelphia, No, 164118,

This lymnaeid resembles some of the elongate forms of the
Stagnicola emarginata complex, especially canadensis and on-
taHensis, The color of the shell and aperture are different from
canadensis and the inner lip is not turned back to form so flat
a projection over the umbilical region. Compared with speci-
mens of ontariensis from the St. La^vrence River below Quebec
the shell is more elongated with longer, narrower, more acute
spire, the inner lip is not flattened and the color is much darker.
A few specimens of the new form resemble certain forms of
8, palustris elodes but the typical forms have a different and
heavier sculpture, a more rounded body whorl, a more acute
spire, and the columellar lip is wider at the lower part and lacks
the heavy, twisted plait of typical elodes.

There is great variation in height of spire and width of shell
but the greatest number of specimens are uniform and it seems

July, 1935] THE NAUTILUS 13

best to recognize this form as a species distinct from either the
palustris or emarginQta complex.

Fossaria obrussa brooksi F. C Baker

Shell differing from Fossaria ohrussa decampi in having a
longer, more acute and t arreted spire, a shorter^ more obese body
whorl, a smaller, rounded aperture and a larger nmbilicns;
whorls shouldered ; color light or dark horn, the aperture choco-
late or coffee colored within ; there are six whorls.
Length 11.5, diam. 6.0, apert- length 5,1, width 2.9 mm. Holotype
9.1 '' 4.7 '' 4.6 '' 2.2mm, Paratype

8.4 '* 4.0 '' 3.8 ** 2.0 mm. Paratype

Type locality: Camp 31, 8 miles from Lomond, Bonne Bay,
Newfoundland- Types: Carnegie Museum, Section of Recent In-
Tertebrates, No. 62. 26764; Museum of Natural History, Univ,
IlL, No. Z. 36339; Academy of Natural Scienees, Philadelphia^
No. 164117,

This distinct little lymnaeid is related to ohrussa^ approaching
most nearly to the race decampL Its long scalariform spire,
short, rounded body whorl, and small rounded aperture will at
once distinguish it from decampi. It is named for Dr, Stanley
T, Brooks who collected the Newfoundland material.

TWO NEW WEST AMERICAN SPECIES OF

NUCULANIDAE

BY IDA S. OLDROYD

Leda austini, n. sp. Pig. 2,

Shell of medium size, concentrically ridged, but the ridges are
few and unevenly distributed ; epidermis thin and in most of the
specimens taken it was worn off leaving patches of chalky white.
Posterior end attenuated, beaked; anterior end rounded and
about i the length of the shell; umbones slightly elevated,
rounded ; ventral margin convex ; dorsal margin concave. Length
12 ; height 5 ; diameter 3 mm.

Range: West Coast of Vancouver Islandj Nootka Light.
2231-3-B ; Porlier Pass 75 fms. ; West of Gabriola Island 25 fms.
Type in the Pacific Biological Station, Nanaimo, B, C, Type
locality off Neck Pointy in 100 fathoms. Specimens from type

locality and from other stations in the Stanford Collection,

14 THE NAUTILUS [VoL 49 (1)

It is nearest to Leda hamata but differs in the shell not as
ventrieose. It is named for Mr. Austin Barkoi% my assistant of
the summer of 1934,

^%- 1' K ""'^^MMESg^^^^M Fig. 2.

Yoldia gardneri, n, sp. Fig, 1,

Shell thin; epidermis a brilliant olivaceous color; valves equal;
lines of growth very faint or absent; base arcuatCj anterior dorsal
profile not rounded; beaks low, inconspicuous. It differs from
Yoldia ensifera in the elongate form, and is much narrower ; the
blade-like processes are not prominent; posterior dorsal profile
straight, while in Yoldia ensifera it is curved. Texture of the
shell more delicate, and the shell more ventricose and elongate.
Length 34; height 12; diameter about 8 mm.

Type in the Pacific Biological Station at Nanaimo^ B. C. Type
locality Gardner Bay, Pender Harbor, in 4 fms. Known only
from type locality. Topotype in Stanford University eoUection,

THREE NEW MICRARIONTAS FROM THE CEN-
TRAL COLORADO DESERT, CALIFORNIA

BY G. WILLETT

During the past winter the writer and his wife have made sev-
eral trips to the chain of hills and mountains consisting of the
Indio and Mecca hills and Orocopia, Chuckwalla and Chocolate
mountains. These lie in the central Colorado Desert, east of
Coachella Valley and Salton Sink-

The only land shell previously recorded from this region is
Micrarionta mille-palmariim Berry^ from Thousand Palms Can-
yon, Indio Hills. The three forms described below are of the
same general group as the Thousand Palms species, the first of
them J however, being much more closely related to it than the
other two. They all, including mille-palmarum^ have the ar-
rangement of papillation on the nuclear whorls as in forms of
M. rowelli^ and may be races of that speeieSj but complete inte-
gradation with it is yet to be shown.